Reaction injection molded (RIM) polyurethanes are well known in the art and have met with substantial commercial success. U.S. Pat. No. 4,218,543 describes the use of relatively high molecular weight hydroxyl group containing materials, aromatic diamines as chain extenders, and isocyanates for the production of RIM parts.
More recently, the activity in the art has been towards the production of polyurea RIM parts. Typically, these parts are made from relatively high molecular weight polyethers which contain amine groups, diamine chain extenders, and isocyanates. Typical of the materials used and the technologies known in the art are those described in U.S. Pat. Nos. 4,396,729, 4,433,067, 4,444,910, 4,530,941, 4,774,263 and 4,774,264. As is known in the art, RIM parts are generally produced from two separate streams. One stream generally contains the isocyanate component, while the other stream contains the amine-containing polyether and the amine chain extender. Amine-containing polyethers where the amine groups are attached to aromatic groups are generally too viscous for use in conventional RIM machinery, while amine-containing polyethers where the amine groups are attached to aliphatic moieties are too reactive to be used alone with conventional aromatic isocyanates. One object of the present invention was to provide a mixture of amine-containing reactant and amine chain extender having a substantially reduced viscosity and thus improved flow characteristics. Additionally, this improvement in flow properties would have to be achieved without adversely affecting the physical properties of the final RIM part.
Compounds having terminal aromatic amine groups and having the general structure: ##STR2## are known. In U.S. Pat. No. 3,808,250, X is defined as oxygen or sulfur, n is an integer of from 2 to 8, and R is defined as an n-valent radical obtained by the removal of hydroxy or mercapto groups from an n-valent polyether or polythioether having a molecular weight of from 600 to 10000. U.S. Pat. Nos. 3,817,940 and 3,929,863 describe similar compounds where R is based on a polyol or polythiol having a molecular weight of less than 600. U.S. Pat. Nos. 3,975,428 and 4,016,143 describe similar compounds prepared by reacting isatoic anhydride with a compound containing at least two hydroxyl groups and at least one tertiary nitrogen group and having a molecular weight of from about 119 to about 1000. Similar compounds are described in U.S. Pat. Nos. 4,136,091, 4,169,206, 4,186,257, 4,228,249 and 4,260,557. Para-substituted compounds are described in U.S. Pat. Nos. 4,504,648 and 4,515,981. Finally, similar para-, meta- and di-meta-substituted compounds are broadly suggested in U.S. Pat. Nos. 4,328,322 and 4,732,959. While all of these references describe that the compounds disclosed can be used to manufacture polyurethane products, none describe the use in a polyurea RIM process.
U.S. Pat. No. 4,847,416 and U.S. application Ser. No. 183,556, filed on Apr. 19, 1988, and U.S. application Ser. No. 266,725, filed on Nov. 3, 1988, describe similar compounds where the aromatic group is connected via ether groups. Both references broadly suggest the use of such amines in a RIM process.